Superlattice phase change memory including Sb2Te3 layers containing Zr

Abstract

A superlattice phase change memory capable of increasing a resistance in a low resistance state is provided. The phase change memory includes a first electrode, a second electrode provided on the first electrode, and a phase change memory layer having a superlattice structure between the first electrode and the second electrode, the superlattice structure including to repeatedly formed layers of Sb 2 Te 3 and GeTe. The phase change memory layer having the superlattice structure includes a Sb 2 Te 3 layer containing Zr in contact with the first electrode.

What is claimed is: 
     
       1. A phase change memory comprising:
 a substrate having a semiconductor device and an insulating film on a surface of the substrate; 
 a first electrode provided on the substrate; 
 a second electrode provided on the first electrode; and 
 a phase change memory layer having a superlattice structure between the first electrode and the second electrode, the superlattice structure including repeatedly formed layers of Sb 2 Te 3  and GeTe, 
 wherein the phase change memory layer having the superlattice structure is in contact with the first electrode and includes Sb 2 Te 3  layers containing Zr. 
 
     
     
       2. The phase change memory according to  claim 1 , wherein the phase change memory layer having the superlattice structure includes one of the Sb 2 Te 3  layers provided in contact with the second electrode. 
     
     
       3. The phase change memory according to  claim 1 , wherein the first electrode and the phase change memory layer having the superlattice structure are processed into columns, and the first electrode is processed in a self-aligning manner with respect to the phase change memory layer having the superlattice structure. 
     
     
       4. The phase change memory according to  claim 1 , wherein an Sb 2 Te 3  layer containing Zr in contact with the first electrode has a thickness of 1 nm to 20 nm. 
     
     
       5. The phase change memory according to  claim 1 , further comprising a selective element between the substrate and the first electrode. 
     
     
       6. The phase change memory according to  claim 1 , wherein all of the Sb 2 Te 3  layers contain Zr. 
     
     
       7. The phase change memory according to  claim 1 , wherein each Sb 2 Te 3  layer containing Zr as expressed below:
   0 wt %< Y <20 wt % 
 where Y is an added amount of Zr. 
 
     
     
       8. A phase change memory comprising:
 a first electrode; 
 a phase change memory layer having a superlattice structure on the first electrode, the phase change memory layer including repeatedly formed layers of Sb 2 Te 3  and GeTe; and 
 a second electrode formed on the phase change memory layer having the superlattice structure, 
 wherein the phase change memory layer having the superlattice structure includes an Sb 2 Te 3  layer in contact with the first electrode and a GeTe layer in contact with the second electrode, and 
 at least one of the Sb 2 Te 3  layers contains Zr. 
 
     
     
       9. The phase change memory according to  claim 8 , wherein the Sb 2 Te 3  layer containing Zr is the Sb 2 Te 3  layer in contact with the first electrode. 
     
     
       10. The phase change memory according to  claim 8 , wherein the Sb 2 Te 3  layer containing Zr is one of the Sb 2 Te 3  layers out of contact with the first electrode. 
     
     
       11. The phase change memory according to  claim 8 , wherein the Zr is uniformly distributed within the Sb 2 Te 3  layer. 
     
     
       12. The phase change memory according to  claim 8 , wherein the Sb 2 Te 3  layer containing Zr has a thickness of 1 nm to 20 nm. 
     
     
       13. The phase change memory according to  claim 8 , wherein the Sb 2 Te 3  layer containing Zr contains Zr as expressed below:
   0 wt %< Y <20 wt % 
 where Y is an added amount of Zr. 
 
     
     
       14. The phase change memory according to  claim 8 , wherein the first electrode is connected to a selective element. 
     
     
       15. The phase change memory according to  claim 14 , wherein the selective element, the first electrode, and the phase change memory layer having the superlattice structure are processed into columns in an array.